Hi will,
在 2021/3/18 17:34, Will Deacon 写道:
On Thu, Mar 18, 2021 at 11:21:24AM +0800, chenxiang wrote:
From: Xiang Chen <[email protected]>
Fix a type "SAC" to "DAC" in the comment of function
iommu_dma_alloc_iova().
Signed-off-by: Xiang Chen <[email protected]>
---
drivers/iommu/dma-iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index af765c8..3bc17ee 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -443,7 +443,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain
*domain,
if (domain->geometry.force_aperture)
dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end);
- /* Try to get PCI devices a SAC address */
+ /* Try to get PCI devices a DAC address */
if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev))
iova = alloc_iova_fast(iovad, iova_len,
DMA_BIT_MASK(32) >> shift, false);
This doesn't look like a typo to me... Please explain.
I think it means double-address cycle(DAC), and in LLD3 452 page, there
is a description about it "PCI double-address cycle mappings Normally,
the DMA support layer works with 32-bit bus addresses, possibly
restricted by a specific device’s DMA mask. The PCI bus, however, also
supports a 64-bit addressing mode, the double-address cycle (DAC)."
Please point it out if i am wrong :)
Best Regards,
chenxiang
Will
.
_______________________________________________
iommu mailing list
[email protected]
https://lists.linuxfoundation.org/mailman/listinfo/iommu
